Eliminating the 1-2-Both-Off Battery Switch

[beetle]

Originally Posted by TrentePieds

I use a 1-2-both . I start off the house bank (the only bank) by using on even dates the "2". position and on odd dates off the "1" position so as to even out the use on the individual batts.

All the house draws are taken from one of the two batts in the same way: Odd dates: "1", even dates: "2".

Never, never use the "both" position.

I'm a little taken-aback at the insistence of a 1-2-Both (and presumably OFF) switch in the electrical system.

The system I put in my boat is designed to be brain-dead simple, the goal being to
1. make it impossible to fry the alternator due to incorrect switch settings
2. isolate the house loads/panel from the starter motor low-voltage on energize and voltage spike on de-energize.
3. isolate the start battery from the house loads
4. provide a way to use the house battery to start the engine if need be
5. recharge the starter battery

It's simplest to use 3 on/off switches to do this. The approach to doing this is:

1. wire the alternator output direct to the house battery, no switch in the path, alternator will always see a battery.

2. house bank is wired through an on/off switch to the house panel. This switch is located near the house bank. House panel never sees the starter motor loads.
https://www.bluesea.com/products/600...th__Knob_-_Red

3. start battery is wired to the starter motor thru an on/off battery switch. I use a small 300 AMP-rated battery switch mounted at the starter battery - the removable key makes it difficult for someone else to start the engine without your permission. House panel never sees the starter motor loads.
https://www.bluesea.com/products/600...with_Key_-_Red

4. a remotely operated hi-power solenoid switch that can parallel the house bank to the starter battery. This energizing circuit breaker/switch for the solenoid is located on the house panel and labeled "Battery Parallel", flipping that breaker on energizes the solenoid located back near the starter battery. It's a 750 AMP rated solenoid (intermittent duty), and is used when the starter battery fails - I turn off all house loads before using that switch to start the engine.
12V Intermittent Duty Solenoid SPST - Cole Hersee Australia

5. to recharge the starter battery you activate the battery parallel switch while the engine is running (15 minutes seems to work) or put in place an automated system such as the Blue Sea automatic charge relay device.

My complaint with TrentePieds approach is the starter motor loads are seen by the house panel, it's possible to fry the alternator if the battery switch is moved to off (or fails) while the engine is running and the alternator field coil is energized, you have to know the date, and remember not to use Both for normal operations. As long as TrentePieds pays attention the setup it will work fine provided a voltage spike won't hurt equipment powered from the house panel. With a three switch approach I don't have to pay attention as I simply can't screw it up - that becomes important when doing long-distance singlehanded racing, you get tired and can make mistakes; it is useful to remove the ability to make mistakes when you can.

- rob

[fdr14127]

I don't understand why people don't upgrade to the latest design solution and be done with it. We installed one of these ( https://www.bluesea.com/products/868...nagement_Panel ) along with the ACR and solved the problem. Two

'always on' circuits run the fridge and bilge pumps when we are not onboard. ACR isolates the house circuits thereby keeping the nav gear and computers isolated and happy.

[beetle]

Originally Posted by fdr14127

We installed one of these ( https://www.bluesea.com/products/868...nagement_Panel ) along with the ACR and solved the problem.

That's a clever setup. In your installation, how did you wire the alternator output? It's not clear to me from the Blue Sea wiring diagram if the input to the starter motor is wired from stud 2, or if that should be the alternator output on stud 2 (or both?). If you bring the alternator into the unit, what happens when the selector is rotated to OFF while the motor is running?

- rob

[rbk]

Originally Posted by beetle

That's a clever setup. In your installation, how did you wire the alternator output? It's not clear to me from the Blue Sea wiring diagram if the input to the starter motor is wired from stud 2, or if that should be the alternator output on stud 2 (or both?). If you bring the alternator into the unit, what happens when the selector is rotated to OFF while the motor is running?

- rob

I have one of these and the only real issue is you cant isolate each bank for each use without adding an on/off from the house bank to the dual panel/switch and another on the start battery side. Combined is combined with this switch alone. Alt should be wired direct to house bank so never any worry about frying your alt. Both circuits are isolated from each other and you can run three 24 hour circuits off the panel/switch.

[jmschmidt]

Get the Blue Sea switch that has a 3 o'clock on position that isolates house from start batteries, the 6 o'clock position gangs all batteries together for an emergency start and, of course, the 12 o'clock is all batteries off. Sorry, don't remember the model number.

[fdr14127]

rob,
well this was done 18mo ago and the boat is up on the cradle so I can't check for sure, (but we have an after market alternator from Moyer Marine which claims to be zap protected). At any rate I 'think' its output is wired to the ACR per Blue Seas' instructions. The house batts are GRP27 AGMs and the starter bat is sealed lead acid and it is charged independently with a marine charger running off the single optional switch installed /now required GFI breaker on the shore mains. The main GFI in turn feeds the Hart inverter which functions as an isolation transformer and charges the house bank. The circuit for the house feeds is off this main switch and is direct to the 12v panels without running to the cockpit and back which improves the distribution no end. In addition we carry a jumper cable for emergency use, which we have only used to jump boats alongside whose batts need help to spin up the their diesel.


I would document this arrangement with a diagram but have never found software to do so. Meantime study the Blueseas diagrams and if you have questions, call them and ask as I did. They know their stuff and gave me all kinds of help.


This boat has more electronics than a Russian trawler, aircraft radio and electronic navigation was my military 'mos', 284.7 (instructor rated).

[SVTatia]

Originally Posted by Stu Jackson

...Since you have MS's wiring diagrams, not sure what you're asking, although your presentation is novel. Good luck.

Thanks Stu. Resolved - as I indicated way back on Post #9 reply to Beetle, I was trying to get away with 2 swicthes, but I'll have 3 as per Beetle's responses and MS diagram.

Originally Posted by beetle

I'm a little taken-aback at the insistence of a 1-2-Both (and presumably OFF) switch in the electrical system.

The system I put in my boat is designed to be brain-dead simple, the goal being to
1. make it impossible to fry the alternator due to incorrect switch settings
2. isolate the house loads/panel from the starter motor low-voltage on energize and voltage spike on de-energize.
3. isolate the start battery from the house loads
4. provide a way to use the house battery to start the engine if need be
5. recharge the starter battery

It's simplest to use 3 on/off switches to do this. The approach to doing this is:

1. wire the alternator output direct to the house battery, no switch in the path, alternator will always see a battery.

2. house bank is wired through an on/off switch to the house panel. This switch is located near the house bank. House panel never sees the starter motor loads.
https://www.bluesea.com/products/600...th__Knob_-_Red

3. start battery is wired to the starter motor thru an on/off battery switch. I use a small 300 AMP-rated battery switch mounted at the starter battery - the removable key makes it difficult for someone else to start the engine without your permission. House panel never sees the starter motor loads.
https://www.bluesea.com/products/600...with_Key_-_Red

4. a remotely operated hi-power solenoid switch that can parallel the house bank to the starter battery. This energizing circuit breaker/switch for the solenoid is located on the house panel and labeled "Battery Parallel", flipping that breaker on energizes the solenoid located back near the starter battery. It's a 750 AMP rated solenoid (intermittent duty), and is used when the starter battery fails - I turn off all house loads before using that switch to start the engine.
12V Intermittent Duty Solenoid SPST - Cole Hersee Australia

5. to recharge the starter battery you activate the battery parallel switch while the engine is running (15 minutes seems to work) or put in place an automated system such as the Blue Sea automatic charge relay device.

My complaint with TrentePieds approach is the starter motor loads are seen by the house panel, it's possible to fry the alternator if the battery switch is moved to off (or fails) while the engine is running and the alternator field coil is energized, you have to know the date, and remember not to use Both for normal operations. As long as TrentePieds pays attention the setup it will work fine provided a voltage spike won't hurt equipment powered from the house panel. With a three switch approach I don't have to pay attention as I simply can't screw it up - that becomes important when doing long-distance singlehanded racing, you get tired and can make mistakes; it is useful to remove the ability to make mistakes when you can.

- rob

Interesting replies - always learning... Thank you all for responding.

[rbk]

Originally Posted by fdr14127

rob,
...which claims to be zap protected)

Most likley ignition protected

Originally Posted by fdr14127

At any rate I 'think' its output is wired to the ACR per Blue Seas' instructions.

Make sure you alt output is NOT wired through an ARC.

[Sailorbob8599]

This sounds very complicated to those of us who are not fully clued in to electrical issues. Why replace one switch with three? I c an understand not wanting the old PERKO style 1-2-all-off which is about 4" or more diameter. I had originally purchased one of these when wiring my boat but opted instead for the smaller BLUE SEAS switch having the same capabilities. Furthermore, I installed it from the back of the panel, giving it a smaller appearance and less protrusion from the face of the panel. But then mine is a smaller boat (12hp single cylinder diesel) using only two batts. One automotive 12v Start, & one Deep Cycle 12v House.
Would love to post a photo but sorry, have never mastered the ability to do so on this forum.

[beetle]

Originally Posted by Sailorbob8599

Why replace one switch with three?

The reasons for using 3 on/off vs a 1-2-both-off are described in my post above.

Things to think about with a 1-2-both-off in your setup:

How do you prevent discharge of the start battery? Typically you'd set the switch to point to the house battery only and that disconnects the start battery from the circuit. If someone accidentally switches to the wrong battery nothing prevents the start battery from being discharged. One way to avoid this is to not have the start battery connected to the switch at all - then you can't accidentally select the start battery and discharge it.

how is power routed from your batteries to the house panel and the starter motor? If the house panel and starter motor share a wire or battery (a typical thing to do if both are on the same circuit back to the common stud on the battery switch) - then when you energize the starter motor a low-voltage condition occurs as the starter motor sucks in large amounts of power from the battery (do the cabin lights dim when you start the motor?). If the house panel and starter are on the same circuit then the house loads have to handle the low-voltage at engine start. It would be nice to have full voltage to the house loads at all time, one way to do that is to isolate the house panel from the starter motor.

When the starter motor is de-energized (the engine has started, you release the start key) the magnetic field in the starter motor winding collapses, the collapse induces a transient hi-voltage spike in the starter motor circuit. That spike will travel over all wires attached to that circuit; if the house panel is part of that circuit then equipment powered on at the panel will have to handle the voltage spike, the spike can damage sensitive electronics. It would be nice to not hit house loads with the spike, one way to do that is to isolate the house from the starter motor - don't share the starter motor wire or start battery with the house panel when starting the engine.

what does the alternator output connect to? If it goes to the switch and you turn the switch off when the alternator is energized, the alternator will overheat and cook itself in a few seconds if the output has nowhere to go. In a typical 1-2-both-off switch wiring approach the output from the alternator is wired to the common stud, and if the switch is turned to OFF while the engine is running (and therefore alternator field coil is energized and the alternator is kicking out power) the alternator no longer sees a battery and will cook itself and now you have a dead alternator. It would be nice to avoid this - one way is to wire the alternator output directly to a battery.

How do you charge the two batteries (banks 1 & 2) with the alternator output? A typical approach with the alternator output wired to the common stud is the switched-to batteries (1, 2, or both) see alternator output. If the switch is set to 1 then only battery 1 is being charged, switching to 2 then only battery 2 is being charged, if set to Both then the charge is split across the batteries. Each time the switch is rotated there is a risk of accidentally hitting OFF and that would be bad for the alternator. It would be nice to never have to rotate the battery selector switch while the engine is running.

If the batteries are of different types or sizes they will accept charge at different rates, it is possible to overcharge one battery while undercharging the other (rare), and you can get power rushing through the switch between batteries if one battery is very low relative to the other and you switch to Both - this can hurt both batteries as they heat up while releasing and absorbing energy. You can't control the individual charge rates if the batteries are joined via the switch set to Both. It might be nice to avoid any over/under charge by aiming the alternator output at the larger bank and charge it fully, with a secondary trickle-over charge mechanism joining the large bank to the small bank to charge the small bank fully.

You would still like a way to use the house battery to start the engine should the engine-start battery fail. If you have isolated the house and the starter battery circuits entirely (to solve the above issues) then you don't have a BOTH option to join the batteries, so you need somewhere a switch that will substitute the house battery for the start battery or parallel the house and start batteries, and route that power to energize the starter motor. That's what the third switch is for - it joins the two banks and sends all available power to the starter motor.

Does the above make the ideas a bit clearer?

- rob

[witzgall]

Our last cruising boat came with a setup which I now consider the best approach to most of these systems.

1. All charging and loads to the house bank. (Except for engine start)
2. Simple on-off switch to the house bank.
3. A DC-DC charger for the starter battery. Originally it was a Xantrex, when that failed, I replaced it with a Balmar Duo Charge.
4. a simple on-off parallel switch to combine in an emergency. never used in two years of cruising.

Starting the engine requires very, very little actual capacity from your starter battery. So once the house batt reaches the set voltage, the Duo Charge kicks in and sends up to 30a to top off the less than 1ah taken from your starter batt. It then maintains it with programmable voltages.

1-2- all switches are a vestige from the past, where the standard procedure was to make two house banks, and switch between the two. There are several reasons why this is not the best approach.



Disclaimer - I work for Balmar, but all of this was before I started working for them.

Chris

[Singularity]

Originally Posted by witzgall

Our last cruising boat came with a setup which I now consider the best approach to most of these systems.

1. All charging and loads to the house bank. (Except for engine start)
2. Simple on-off switch to the house bank.
3. A DC-DC charger for the starter battery. Originally it was a Xantrex, when that failed, I replaced it with a Balmar Duo Charge.
4. a simple on-off parallel switch to combine in an emergency. never used in two years of cruising.

This is what I'm doing while converting the boat to 24v. Insofar as I'll retain 2 discreet 12v batteries (1 for starter, 1 for generator) I won't even have step #4 (on-off-parallel switch). I'll just jump or physically translocate the 12v batteries in the event of a start battery failure.

It took me forever to realize how little sense the 1/2/both-acr-3 switch-combiner system makes if you're willing to accept other compromises. Just that the 1-2-both-off stuff gets the most bandwidth.

[sailah]

Originally Posted by Stu Jackson

This is a newer primer for boat system wiring design with a thorough digram: Building a Good Foundation (October 2016)
http://forums.sailboatowners.com/ind.../#post-1332240

I am redoing much of my charging system this year, prompted by a failed AGM starter battery. I ended up replacing all batteries, 2 120 Ah golf carts for house and a 31 for start.

But then I started looking into the Balmar SG200.

Well, $1000 later and I am basically following Maine Sails excellent schematic almost exactly.

I used the SG200 instead of Victron
I don't have solar
My bank is half the size
I have a windlass

Other than that is almost exactly what I have. Been loading up on bus bars, crimps, terminals etc.

The only thing I did not like was the 3 switches. I have a medium Perko like everyone else. But I really don't like the switching from start to house all the time. So I found the Blue Sea 5511e which does exactly what I want.

Switches on house, switches on start, engines start (and ACR drops house while starting) and then everything else is running on house. Alternator feeds house bank first, then ACR tops up start bank once voltage has been reached.

And when I want to shut down and leave the boat I just kill it. That way I'm never tempted to cheat and start the boat on house bank because I'm too lazy to walk down below.

Seems like the best of all worlds and added benefit that the Blue Sea fits the Perko cutout in my nav station.

The only thing it wouldn't do, that you want, is fully isolate the reserve. In this scenario I don't want to isolate, I want to use start for starting only and have parallel as an option.

I decided not to put the ON/OFF switch Maine Sail has between house and bus. Now I'm seeing the wisdom of that since if I needed to use start bank for other things and house bank was dead if they are paralleled it would draw down start pretty quickly.

Anyways that's what I'm doing and just getting started with parts.

[Q Xopa]

Originally Posted by Singularity

This is what I'm doing while converting the boat to 24v. Insofar as I'll retain 2 discreet 12v batteries (1 for starter, 1 for generator) I won't even have step #4 (on-off-parallel switch). I'll just jump or physically translocate the 12v batteries in the event of a start battery failure.

It took me forever to realize how little sense the 1/2/both-acr-3 switch-combiner system makes if you're willing to accept other compromises. Just that the 1-2-both-off stuff gets the most bandwidth.

Im pretty much going through the same issue myself.
But just to add an extra layer of complexity to this issue.
Im also doing a 24v conversion.
Im not considering a 1 2 B switch. Im just doing individual on/off switches for individual banks.
At the moment I have my 24v Alternators connected to a B2B2412 charger to the starter batt.
Then the House bank connected through an ACR.
Im considering my options for Starter power back up. Obviously cant do a combine option.
Ive already converted to a 24v windlass.
The simplist solution I can see is Id like to just convert to a 24v starter, or even just running a 12v starter at 24v. Im looking at possible options.
Always open to suggestions.

[blubaju]

With to many single switches you are only confusing people and make a wonderfull opportunity for wrong settings.

I have a catamaran, each engine a starter battery, house battery and dedicated electronics battery

all batteries of same type

sterling alternator to battery charger (speeds up charging considerably

every alternator is Westmarine ZAP-STOP Alternator Protector protected, this 30$ is worth every cent

every battery bank connects to the main 12V bus via battery combiner, hence when charging voltage rises they are automatically combined BUT the internal relay power supply is broken with a small switch if for any reason I want that battery off-grid for sure

That means, full power of all combined batteries until a certain discharge level, then the combiners separate. If the 100A anchor windlass pulls to much, the electronics will not die. Same with the engines, but 30HP Yanmars do not draw much or long.

Usually battery switches are set "OFF", 1,2, both are emergency settings except the engine switches

1 sets dedicated battery to engine, 2 the "house-bus" to engine "OFF work on the engine "BOTH" with a low V Battery

2 more switches (dis)connect the battery banks to the bus, these are usually "OFF"

I would not like to do this with "ON_OFF" switches alone